Mining Bees

Updated: 28th February 2021

Tawny mining bee – <i>Andrena fulva</I> on stoneAbove: Tawny mining bee – Andrena fulva

Mining bees (‘Andrenidae’) are one of the largest groups of solitary bees. It is believed to consist of over 4500 known species of bees across the world.

They vary greatly in size, from nearly an inch long to extremely tiny - those from the genus Perdita can be smaller than 0.1 inches.   

Pictured above is the tawny mining bee – Andrena fulva.  Adults are endearing little creatures, the females being reddish orange in colour, with black undersides, whilst males are duller, and smaller than females.

Mining Bee - Andrenidae genera

There are 13 genera in the family Andrenidae.  Included among them are Andreninae, Protandrenini, Panurgini, Perditini, Calliopsis and Oxaeinae.

Where do mining bees nest?

All Andrenidae nest in the earth and line their nests with a waterproof substance that also acts to protect the nest cells from bacteria.  The type of location varies considerably.  some may prefer coastal areas and sand dunes.  Others are more common on woodland edges or in gardens.

The Ashy mining bee, Andrena cineraria is thought to prefer sloping sites, whereas the Grey-patched mining bee, Andrena nitida will nest in formal lawns but also sheep-grazed hillsides.

In gardens, evidence of mining bees may be seen if you come across little mounds of earth in lawns, borders, or even in pots, resembling worm casts.  Alternatively, you may see holes in a bare patch of soil.  

The nests will not cause any damage in soil or in gardens, and indeed, they should be welcomed. They rarely, if ever sting, and provide an excellent pollination service. The use of pesticides in lawns to deal with them is not recommended.

Nests are very short lived, do not damage plants, and many lawn pesticides are actually harmful to earthworms.

The depth of the tunnel made by mining bees depends on the species, with nests commonly measure 6 inches but up to a couple of feet deep.

Typical life cycle of common species

Adults emerge from hibernation in Spring, having hibernated through the winter. After mating, the female seeks a place to nest. Like the other female solitary bees, she sets about making egg cells: in each one she lays an egg and provides both pollen and nectar on which the individual larva can feed.

Each individual egg cell is made, provisioned, then sealed up before the next cell is made.

She will usually lay about 5 eggs.

Adults may be active for 6 – 8 weeks of the year, and the new adults that emerge will need to hibernate over winter again, to re-emerge in Spring. Although solitary, some species may nest in aggregations.  

Some common questions about mining bees in the garden

What do mining bees eat?

Answer: Like other bees, they eat nectar and pollen from flowers, but the foraging preferences (the particular flowers they like to forage from) will differ depending on the species.  Some are generalists (meaning they will feed from many types of flowers) whilst others are specialists, feeding only from select flower species.

Are mining bees aggressive or dangerous?
Answer: I am not aware of any aggressive or dangerous species.

How big are mining bees?
Answer: It depends on the species and the country.  They may range from a few millimeters to almost an inch in some parts of the world.

How do I get rid of mining bees?
Answer: Why do that?  They are not dangerous and bees need all the help they can get.  Why not leave them alone?

Read about the Chocolate Mining Bee

chocolate mining bee image linking to page about this species

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